Mobile devices, for example mobile phones and mobile media players, are becoming more and more compact and at the same time the number of functions provided by those mobile devices is rising permanently. For adjusting and using the functions of the mobile device, the mobile device provides several control devices, for example a touchscreen or buttons. However, the space for providing these control devices is limited and when the mobile device is accommodated in a pocket, the user has to fetch out the mobile device before the control devices can be operated.
Therefore, there is a need to provide additional and more convenient operating devices for mobile devices.